Question

Have a friend hold a ruler by one end, letting the other end hang
down vertically. At the lower end, hold your thumb and index finger
on either side of the ruler, ready to grip it. Have your friend
release the ruler without warning. Catch it as quickly as you can.
If you catch the ruler 6.9 cm (~2.7 inches) from the lower end,
what is your reaction time?
Answer in s